Top Ad unit 728 × 90

Radiology News


Trauma Metacarpophalangeal joint

Adolescent male with sporting injury to thumb clinically

Xray shows widening of the ulnar side of thumb MCP joint with no bony injury  and sof tissue haziness in periarticular location-possibly sprain in the  form of collateral ligament injury, sesamoids though atypical in position are not injured. MRI would  help delineate the ligamentous injury and occult bone marrow oedema. Case submitted by Dr MGK Murthy.

Teaching points--
Hinged(condyloid joint) with shallow proximal phalanx base articulation with spherical(thumb rather quadrilateral)metacarpal head
Thumb MCP gets more often injured than relatively stable finger MCP
Factors for stability include soft issue contractility including volar plate, true and accessory collateral ligaments , sagittal band, dorsal capsule, extrinsic and intrinsic tendons
Range permitted usually is 30 deg hypertext, 120 deg flexion, 30 to 40deg mediolateral laxity and small rotation
Volar plate is most susceptible for injury
Usually trauma leads to sprains in the form of  collateral ligament  injury(25 to 40%)
When dislocated, dorsal more common than palmar
Dorsal is described simple if no soft tissue interposed and complex other wise
Two level dislocations are when concomitant Bennett or interphalangeal joint is involved as well
Xray is adequate particularly if additional views (to AP/Lat and Obique ) are added
(a) Brewertons view- place proximal phalanx touching on the cassette after flexing MCP joint to 65 degrees and angulate the beam 15 degress from ulnar to radial side
(b) True lateral of the digit/thumb concerned rather than hand
  1. Hands have 5 sesamoids (nodule of calcium within tendons or joint capsule) , with 2 at MCP joint, and 1 at interphalangeal joint of thumb, with  rest at MCP joints of index and small fingers
  2. Position of the sesamoids while could help, decide the articulation postion, they usually do not dislocate , however could be fractured, infected, inflamed, or turn neoplastic 
Trauma Metacarpophalangeal joint Reviewed by Sumer Sethi on Thursday, May 19, 2011 Rating: 5

No comments:

All Rights Reserved by Sumer's Radiology Blog © 2014 - 2015
Powered By Blogger,

Contact Form


Email *

Message *

All contents copyrights with Sumer Sethi. Powered by Blogger.